WASHINGTON  When Congress opened its inquiry last year into how organizers of the Sept. 11 terror attacks foiled U.S. intelligence agencies, there was widespread speculation that it would be a whitewash.

Some skeptics said the inquiry's leaders were too cozy with the intelligence community to be effective critics. House Intelligence Committee Chairman Porter Goss, a Florida Republican, is a former CIA officer; Senate Intelligence Committee Chairman Bob Graham, D-Fla., is a close friend of Goss. Relatives of Sept. 11 victims worried that members of Congress wouldn't be willing to reveal the failings of government agencies.

On Thursday, many of those relatives thanked the committee members for a scathing assessment of the nation's intelligence failures, but sharply questioned why the Bush administration refused to allow more information to be released.

"As someone who voted for President Bush, I'd really like to call on him, man to man ... to produce the documents that have been requested," said a tearful Bill Harvey of New York City. He lost his wife, Sara Manley, at the World Trade Center.

The family members joined Graham for a press conference in which the senator, who is running for president, accused the Bush administration of hampering the investigation by holding back information and refusing to allow portions of the report to be declassified. Earlier this month, leaders of an independent commission that is continuing the Sept. 11 inquiry also complained of difficulty obtaining information from the administration.

Graham contended that the foot-dragging is slowing efforts to implement reforms in the intelligence agencies. "I remain deeply disturbed by the amount of material that has been censored from this report," he said.

White House press secretary Scott McClellan insisted that administration officials "worked to make sure as much information as possible could be shared publicly." He estimated that "nearly 80%" of the congressional report was made public. "Only the most sensitive of national security information, which could potentially compromise the sources and methods or otherwise harm our national security, is not being declassified," he said.

But key members of the president's own party said they think more of the report should have been made public. "There's a lot of information that's not in here that should be," Sen. Richard Shelby, R-Ala., said.

Goss, who pushed for release of much information that the administration wanted to hold back, said he felt some omissions were justified for national security reasons. But the former spy criticized the intelligence agencies' "culture of not releasing information."

The intelligence committee spent nine months compiling the report and seven more haggling with the White House over how much could be released. It outlined some of the obstacles to its inquiry in a six-page appendix to the report. It said the administration and intelligence officials denied access to information on a number of items, including the intelligence agencies' budget requests to the White House and military actions that had been planned against Osama bin Laden, the alleged architect of the Sept. 11 attacks.

Some intelligence agencies coached employees before they were interviewed by congressional staff and sent monitors to the interviews to prevent certain questions from being answered, the report said.

The biggest controversy concerns a 28-page section of the report that was almost completely blanked out. It discusses possible support from a foreign government for men who helped hijack a plane that crashed into the Pentagon. Committee members said they are legally barred from identifying a country, but elsewhere in the report the hijackers' benefactor is identified as an employee of Saudi Arabia's civil aviation agency.

Prince Bandar bin Sultan, the Saudi ambassador to the United States, denied any involvement in the Sept. 11 plot by his government. The "blanked-out pages are being used by some to malign our country," Bandar said. "Saudi Arabia has nothing to hide. We can deal with questions in public, but we cannot respond to blank pages."